In a sign of burgeoning economic ties, a group of South and North Korean officials jointly visited South Korean companies in China and Vietnam, the Unification Ministry said Monday.

The delegation consisting of seven South Koreans and as many North Koreans working at a joint management office of the Kaesong industrial complex visited the companies in Shanghai, Shenzen, Guangzhou, Hanoi and Ho Chi Mihn City for 10 days from June 19. They were given tours and received briefings on the companies’ operations, the ministry said.

“It was a good opportunity for North Korean economic officials to learn from rapidly developing socialist countries,” a senior ministry official said, asking to remain anonymous. “They must have shared the need to further promote inter-Korean economic ties.”

It marks the first time that South and North Korean officials made an overseas trip together to assess the development of South Korean companies, the official added.

In the North Korean border city of Kaesong, a capitalist enclave, South Korean businesses use low-cost skilled North Korean labor to produce goods. Monthly production in the complex exceeds US$10 million.

Currently, 23 South Korean companies employ about 15,000 North Korean workers at the site developed on a trial basis. These include construction workers and workers at a management office. The number of North Korean workers is expected to increase to more than 350,000 when the complex becomes fully operational in 2012.